1. Field of the Invention
The present invention relates to a liquid transport apparatus which transports a liquid, a liquid transport head which transports a liquid, and a piezoelectric actuator which deforms when a potential is applied thereto.
2. Description of the Related Art
In an inkjet printer (liquid transport apparatus) described in US Patent Application Publication No. US2007/0076054 (corresponding to Japanese Patent Application Laid-open No. 2007-118585), a vibration plate serving also as a common electrode is arranged to cover pressure chambers, a piezoelectric layer is joined to an upper surface of the vibration plate, and on an upper surface of the piezoelectric layer, individual electrodes are formed at portions facing the pressure chambers. When a driving potential is applied to the individual electrode, a potential difference occurs between the individual electrode and the vibration plate as the common electrode kept at ground potential, and due to this potential difference, an electric field in a thickness direction is generated in a portion, of the piezoelectric layer, sandwiched between these electrodes. Due to the electric field, this portion of the piezoelectric layer contracts in a horizontal direction, and as a result, portions, of the piezoelectric layer and the vibration plate, facing the pressure chamber deform as a whole so as to project toward the pressure chamber side to reduce the volume of the pressure chamber. This increases the pressure of ink in the pressure chamber, resulting in the jetting of the ink from a nozzle communicating with the pressure chamber.
However, in the inkjet printer described in US Patent Application Publication No. 2007/0076054, since the piezoelectric layer and the vibration plate deform so as to project only toward the pressure chamber side from the horizontal state, a change amount of the volume of the pressure chamber caused by the deformation of the piezoelectric layer and the vibration plate is small and thus a high pressure cannot be applied to the ink in the pressure chamber.